U.S. patent number 10,323,688 [Application Number 14/982,301] was granted by the patent office on 2019-06-18 for hydro dynamic bearing device.
This patent grant is currently assigned to Mitsubishi Hitachi Power Systems, Ltd.. The grantee listed for this patent is Mitsubishi Hitachi Power Systems, Ltd.. Invention is credited to Kenichi Hattori, Makoto Hemmi, Kengo Iwashige, Tateki Nakamura, Yasunori Shigenaga, Takayasu Tanaka, Kenichi Tohrisawa, Kenichi Tomita, Yukihiro Yamamoto, Tomoaki Yamashita.
United States Patent |
10,323,688 |
Tanaka , et al. |
June 18, 2019 |
Hydro dynamic bearing device
Abstract
A hydro dynamic bearing device comprising an upper half of a
main bearing and a lower half of the main bearing, wherein the
upper half of the main bearing is lined with a low-strength metal
such as a Babbitt metal, wherein a circumferential groove is formed
in the lower half of the main bearing, and wherein the low-strength
metal of the upper half of the main bearing, which is formed at a
region opposed to a downstream side of the circumferential groove
formed in the lower half of the main bearing, is partially removed
to cause a high-strength bearing base metal to be partially
exposed.
Inventors: |
Tanaka; Takayasu (Yokohama,
JP), Hattori; Kenichi (Yokohama, JP),
Yamamoto; Yukihiro (Yokohama, JP), Tomita;
Kenichi (Yokohama, JP), Iwashige; Kengo
(Yokohama, JP), Tohrisawa; Kenichi (Yokohama,
JP), Shigenaga; Yasunori (Yokohama, JP),
Yamashita; Tomoaki (Tokyo, JP), Hemmi; Makoto
(Tokyo, JP), Nakamura; Tateki (Yokohama,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Mitsubishi Hitachi Power Systems, Ltd. |
Yokohama-shi, Kanagawa |
N/A |
JP |
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Assignee: |
Mitsubishi Hitachi Power Systems,
Ltd. (Yokohama-shi, JP)
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Family
ID: |
51178714 |
Appl.
No.: |
14/982,301 |
Filed: |
December 29, 2015 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20160131185 A1 |
May 12, 2016 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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14326180 |
Jul 8, 2014 |
9255604 |
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Foreign Application Priority Data
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Jul 9, 2013 [JP] |
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2013-143267 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16C
33/1065 (20130101); F16C 33/046 (20130101); F16C
33/107 (20130101); F16C 33/1045 (20130101); F16C
32/064 (20130101); F16C 33/121 (20130101); F16C
17/022 (20130101); F16C 33/14 (20130101); F16C
33/24 (20130101) |
Current International
Class: |
F16C
32/06 (20060101); F16C 33/14 (20060101); F16C
33/24 (20060101); F16C 33/12 (20060101); F16C
33/10 (20060101); F16C 33/04 (20060101); F16C
17/02 (20060101) |
Field of
Search: |
;384/95,120,129,273,276,286,291,313,317,321,316 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2 020 783 |
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Nov 1979 |
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GB |
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50-54746 |
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May 1975 |
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JP |
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62-67325 |
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Mar 1987 |
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JP |
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8-93769 |
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Apr 1996 |
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JP |
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9-126227 |
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May 1997 |
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JP |
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9-273555 |
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Oct 1997 |
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JP |
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2000-145781 |
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May 2000 |
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JP |
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2000145781 |
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May 2000 |
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JP |
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2004-92878 |
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Mar 2004 |
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JP |
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2009222210 |
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Oct 2009 |
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JP |
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2010-116953 |
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May 2010 |
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JP |
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2013-104546 |
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May 2013 |
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JP |
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Other References
Extended European Search Report dated Nov. 18, 2014 (four (4)
pages). cited by applicant .
Translation of JP 2000-145781. cited by applicant .
Translation of JP 8-93769. cited by applicant .
European Office Action dated Mar. 1, 2016 Six (6) pages) issued in
application No. 14 176 176.7. cited by applicant.
|
Primary Examiner: Charles; Marcus
Attorney, Agent or Firm: Crowell & Moring LLP
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser.
No. 14/326,180, filed Jul. 8, 2014, which claims priority from
Japanese Patent Application No. 2013-143267, filed on Jul. 9, 2013,
the content of which is hereby incorporated by reference into this
application.
Claims
The invention claimed is:
1. A method for suppressing erosion of a hydro dynamic bearing
device, the method comprising: cutting out the hydro dynamic
bearing device; and exposing a bearing base metal material to a
lubricant during operation, wherein the bearing device comprises an
upper half of a main bearing and a lower half of the main bearing,
the upper half of the main bearing and the lower half of the main
bearing being respectively provided with a metal, which is softer
than a material of a shaft to be supported by the hydro dynamic
bearing device, formed on an inner circumferential side surface of
a bearing base metal thereof, and the lower half of the main
bearing having a substantially semi-circumferential lubrication
groove, in which a lubricant oil flows, provided at a center of a
bearing width direction and in a circumferential direction, and the
cutting out step cuts out a port of the metal of the upper half of
the main bearing at a region of a upstream side of the upper of the
main bearing opposed to a downstream side outlet of the
substantially semi-circumferential lubrication groove of the lower
half of the main bearing so that the bearing base metal is
partially exposed at the region.
2. A method for suppressing erosion of a hydro dynamic bearing, the
method comprising: removing a part of the metal of the hydro
dynamic bearing device; and forming a metal shield, wherein the
hydro dynamic bearing device comprises an upper half of a main
bearing and a lower half of the main bearing, the upper half of the
main bearing and the lower half of the main bearing being
respectively provided with a metal, which is softer than a material
of a shaft to be supported by the hydro dynamic bearing device,
formed on an inner circumferential side surface of a bearing base
metal thereof, and the lower half of the main bearing having a
substantially semi-circumferential lubrication groove, in which a
lubricant oil flows, provided at a center of a bearing width
direction and in a circumferential direction, the step of removing,
removes the part of the metal from the upper half of the main
bearing at a region of an upstream side of the upper half of the
main bearing opposed to a downstream side outlet of the
substantially semi-circumferential lubrication groove of the lower
half of the main bearing, and the step of forming, forms the metal
shield so as to have a strength higher than the metal at the region
of the upper half of the main bearing at which the metal is
partially removed.
Description
TECHNICAL FIELD
The present invention relates to a hydro dynamic bearing device
and, particularly, to a hydro dynamic bearing device suitable for a
large sized drive machine or rotary electric machine.
BACKGROUND ART
A rotary shaft of a drive machine such as a turbine, or of a rotary
electric machine such as a turbine generator is supported by hydro
dynamic bearing devices (journal bearing devices). In recent years,
in order to comply with demands for electric power in, for example,
developing countries, the capacity of powertrains (a couple of
turbine and generator) alone tends to be increased. According to
this, the width or diameter of the bearing device supporting the
rotary shaft also tends to be increased.
In the hydro dynamic bearing device that is used in the turbine or
turbine generator, a bearing surface of a lower half of a main
bearing is formed with a groove at the center of a bearing width
and in a circumferential direction (for example, JP-A No. Hei
8-93769). In a case where the circumferential groove is not
provided, along with an increase in the bearing width, a pressure
receiving area of the shaft is increased to increase force that
lifts the shaft up, and stability of the bearing tends to be lost.
However, by the provision of the circumferential groove at the
center of the bearing width, formation of a fluid film of lubricant
oil is stimulated and the stability of the bearing can be
maintained.
Moreover, JP-A No. Sho 62-67325 (Patent Literature 2) describes
that, in a journal bearing used in a steam turbine or the like, in
order to prevent a bearing inner circumferential surface from being
eroded by vapour bubbles produced in lubricant oil, an inner
circumferential surface of an upper half part of a bearing body is,
for example, heat-treated to thereby enhance a surface hardness and
homogenize a structure, or a hardened layer is formed on the inner
circumferential surface of the upper half part of the bearing body
by plating or the like.
CITATION LIST
Patent Literature
[Patent Literature 1] JP-A No. Hei 8-93769
[Patent Literature 2] JP-A No. Sho 62-67325
SUMMARY OF INVENTION
Technical Problem
According to the increase of the bearing diameter, a peripheral
speed of the shaft is increased. For example, in a case where a
shaft diameter is 550 mm and operation is carried out at 60 Hz, the
peripheral speed exceeds 100 m/sec. By such an increase in the
peripheral speed of the shaft, a velocity of the flow of the
lubricant oil between the shaft and the bearing surface is also
increased and, moreover, generation of a cavitation area between
the shaft and the bearing surface is brought about. A discontinuous
portion is formed on the inner circumference of the bearing surface
due to an oil supply groove, an oil drain groove, etc. In this
discontinuous portion, particularly by an increase in the velocity
of the flow of the lubricant oil in the circumferential groove,
erosion due to collision of the lubricant oil and cavitation
erosion may be produced.
Particularly in a case of a large sized drive machine or rotary
electric machine, in order to protect a shaft, an entire inner
circumference of a bearing is subjected to lining treatment using a
low-strength metal (Babbitt metal (white metal)) softer than a
material for the shaft (steel). This low-strength metal is
susceptible to erosion due to the collision of the lubricant oil
and cavitation erosion.
In the Patent Literature 2, in order to prevent the bearing inner
circumferential surface from being eroded by the cavitation, the
hardened layer is formed on the entire inner circumferential
surface of the upper half part of the bearing body by the
heat-treatment, plating, etc. However, in order to protect the
shaft, it is preferable to provide a metal such as a Babbitt metal
on the bearing surface of the upper half of the main bearing.
The object of the present invention is to provide a hydro dynamic
bearing device in which a bearing surface of an upper half of a
main bearing is also lined with a low-strength metal such as a
Babbitt metal and in which even if a bearing diameter is increased,
erosion by lubricant oil and cavitation erosion can be
suppressed.
Solution to Problem
A hydro dynamic bearing device according to the present invention
comprising: an upper half of a main bearing and a lower half of the
main bearing, wherein the upper half of the main bearing is lined
with a low-strength metal, wherein a circumferential groove is
formed in the lower half of the main bearing, and wherein the
low-strength metal of the upper half of the main bearing, which is
formed at a region opposed to a downstream side of the
circumferential groove formed in the lower half of the main
bearing, is partially removed to cause a high-strength bearing base
metal to be partially exposed.
Advantageous Effects of Invention
According to the present invention, in the hydro dynamic bearing
device in which the bearing surface of the upper half of the main
bearing is also lined with the low-strength metal such as a Babbitt
metal and, even if the bearing diameter is increased, it is
possible to suppress the erosion by the lubricant oil and the
cavitation erosion.
Other problems, constitution, and effects will become apparent from
the following description of an embodiment.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a sectional view of a hydro dynamic bearing device of an
embodiment of the present invention at the center of a bearing
width;
FIG. 2 is a top plane view of a lower half of a main bearing of the
hydro dynamic bearing device according to the embodiment of the
present invention;
FIG. 3 is a top plane view of an upper half of the main bearing of
the hydro dynamic bearing device according to the embodiment of the
present invention (a top plane view of the upper half of the main
bearing at the time when a surface of the upper half of the main
bearing which is opposed to the lower half of the main bearing is
faced upward);
FIG. 4 is a perspective view of the lower half of the main bearing
of the hydro dynamic bearing device according to the embodiment of
the present invention;
FIG. 5 is a perspective view of the upper half of the main bearing
of the hydro dynamic bearing device according to the embodiment of
the present invention (a perspective view of the upper half of the
main bearing at the time when the surface of the upper half which
is opposed to the lower half of the main bearing is faced upward);
and
FIG. 6 is a partially enlarged sectional view of the upper half of
the main bearing of the hydro dynamic bearing device according to
the embodiment of the present invention.
DESCRIPTION OF EMBODIMENTS
An embodiment of the present invention will be explained
hereinafter with reference to the drawings.
As shown in FIG. 1, a hydro dynamic bearing device of this
embodiment is divided vertically into two, namely, an upper half 1b
of a main bearing and a lower half 1a of the main bearing. Each of
the upper half 1b of the main bearing and the lower half 1a of the
main bearing has a bearing base metal whose inner circumferential
surface, namely, entire circumferential bearing surface, is lined
with a metal (a Babbitt metal or the like) of about a few
millimeters having strength lower than the bearing base metal.
Moreover, as necessary, a liner is provided on the inner
circumferential surface of the bearing base metal. In this case, a
low-strength metal is lined on the liner.
The hydro dynamic bearing device of this embodiment is provided, at
the loaded lower half 1a of the main bearing, with an oil supply
path 3 for supplying lubricant oil and an oil drain path 4 for
draining a portion of the lubricant oil. The lubricant oil supplied
from the oil supply path 3 flows into circumferential grooves 2a,
2b that are formed in the bearing surface, namely, the inner
circumferential surface of the low-strength metal. Then, the
lubricant oil from the circumferential grooves 2a, 2b is supplied
between the bearing surface and a shaft 8 and a fluid film is
formed. Thereby, the rotary shaft 8 is rotatably supported, via the
fluid film, by the upper half 1b of the main bearing and the lower
half 1a of the main bearing.
As shown in FIGS. 2 and 4, the lower half 1a of the main bearing is
provided with horizontal space portions 7 on the oil supply path 3
side and the oil drain path 4 side in the vicinity of a mating
surface of the lower half 1a of the main bearing relative to the
upper half 1b of the main bearing. Moreover, wide-width
(substantially entire width of the bearing) oil supply/drain
grooves 6a that continuously connect the horizontal space portions
7 and the bearing surface of the lower half 1a of the main bearing
are formed. Moreover, at the center of an axial direction of the
lower half 1a of the main bearing, a circumferential groove 2a for
ensuring vibration-stability of the rotary shaft 8 is provided
along a rotational direction. Moreover, the bearing surface of the
lower half 1a of the main bearing is formed, at a lowermost part
thereof, with oil supply holes 10 on the both sides of the
circumferential groove 2a. At the time of startup of the drive
machine or rotary electric machine, the lubricant oil is supplied
from these oil supply holes 10 to lift up the rotary shaft 8 and
prevents the rotary shaft 8 from being rotated from a state where
the shaft 8 and the bearing surface of the lower half 1a of the
main bearing adhere together.
As shown in FIGS. 3 and 5, the upper half 1b of the main bearing is
formed with two wide-width circumferential grooves 2b. In lieu of
these circumferential grooves 2b, one wide-width circumferential
groove may be employed. Moreover, the upper half 1b of the main
bearing is provided with wide-width (substantially entire width of
the bearing) oil supply/drain grooves 6b that are formed so as to
gently extend to the bearing surface of the upper half 1b of the
main bearing from a mating surface of the upper half 1b of the main
bearing relative to the lower half 1a of the main bearing.
Moreover, an upstream side of the upper half 1b of the main bearing
which is mated with a downstream side (a side at which the oil
supply path 3 is provided) of the lower half 1a of the main bearing
is provided, at a region of the upstream side which is opposed to
the circumferential groove 2a of the lower half 1a of the main
bearing, with a notch portion 9 that is formed by cutting out a
low-strength metal of the region. The details are explained with
reference to FIG. 6.
As shown in FIGS. 2 to 5, each of the outer circumferential
surfaces of the upper half 1b of the main bearing and lower half 1a
of the main bearing is formed in a spherical shape 15 and is
provided with a spherical seat (abbreviated in the drawings).
Erosion by the lubricant oil and cavitation erosion are produced
mainly at a discontinuous part of a portion extending to the upper
half 1b of the main bearing from the lower half 1a of the main
bearing. Particularly, they are produced at an opposed area of the
upper half 1b of the main bearing which is located on an outlet
side of the circumferential groove 2a of the lower half 1a of the
main bearing. Thus, in this embodiment, a position at which the
erosion by the lubricant oil and the cavitation erosion are
produced is confirmed by test or the like and, in addition to the
erosion-produced region, the low-strength metal lined on the
bearing surface of the upper half 1b of the main bearing is
previously removed partially.
Namely, as shown in FIG. 6, the upper half 1b of the main bearing
has a low-strength metal 12 lined on the inner circumferential
surface of a bearing base metal 11 thereof. Incidentally, in FIG.
6, section hatching of the bearing base metal 11 is omitted. The
circumferential grooves 2b are provided in the inner
circumferential surface of this low-strength metal. As shown in
FIGS. 3, 5, and 6, the low-strength metal 12 at an inlet region of
the upper half 1b of the main bearing that is opposed to the outlet
of the circumferential groove 2a of the lower half 1a of the main
bearing is previously notched partially, whereby the notch portion
9 is formed. By previously providing the notch portion 9 in this
way, the bearing base metal (base metal made of steel, stainless
steel, or high-carbon chromium steel) that has strength higher than
the low-strength metal is made partially exposed. Therefore, in
this notch portion 9, an effect equivalent to an effect that a
shield is formed of a partially high-strength metal is
obtained.
Therefore, even in the state where the low-strength metal is lined
on the substantially entire circumference of the bearing surface,
it is possible to suppress the erosion of the upper half 1b of the
main bearing by the lubricant oil and the damage of the upper half
1b of the main bearing by the cavitation erosion and to prolong the
life-time of the bearing. In a case where the notch portion 9 is
not provided, it is conceivable that, after prolonged operation,
the bearing base metal 11 is exposed due to the erosion by the
lubricant oil and the damage by the cavitation erosion, in the same
manner as in the case of forming the notch portion 9. However, by
previously forming the notch portion 9 as in this embodiment, it is
possible to previously prevent any foreign material from entering
between the bearing surface and the shaft by peeling and shaving of
the low-strength metal during operation.
Incidentally, while the low-strength metal is partially removed to
cause the high-strength bearing base metal to be exposed in the
above-mentioned embodiment, the low-strength metal is partially
removed and the region in which the low-strength metal is partially
removed may be shielded by a high-strength metal (for example, a
metal higher in strength of material by a few times).
Incidentally, the present invention is not limited to the
above-mentioned embodiment and includes various modifications. For
example, the above-mentioned embodiment has been explained in
details in order to facilitate understanding of the present
invention and is not always limited to an embodiment including all
the elements that have been explained. Moreover, it is possible to
replace a portion of a structure of a certain embodiment with a
structure of another embodiment and it is possible to add a
structure of a certain embodiment to a structure of another
embodiment. Moreover, it is possible to add a structure of a
certain embodiment to a portion of a structure of another
embodiment, delete the portion of the structure of the embodiment,
and replace the portion of the structure of the embodiment with a
structure of another embodiment.
REFERENCE SIGNS LIST
1a: Lower half of main bearing
1b: Upper half of main bearing
2a, 2b: Circumferential groove
3: Oil supply path
4: Oil drain path
6a, 6b: Oil supply/drain groove
7: Horizontal space portion
8: Rotary shaft
9: Notch portion
10: Oil supply hole
11: Bearing base metal
12: Low-strength metal
* * * * *